I was talking to some other parents in our gifted chapter who said they had their kids practice for the CogAT on the computer and their scores went up a lot the second time. These kids are in the gifted magnet. The district itself says it's an "ability" test not an IQ test. But then they call it a "gifted" program. They should just call it an "Honors" program for high achievers and leave it at that.
If some people prep their kids and those are the kids who get in, I would do it as well if prepping raises scores. Luckily I didn't have to do that because the district said they'd take outside WISC scores.